Systems have been provided for determining the movements of mobile items. For example, tags have been disposed on articles in department stores to signal when merchandise is being removed from the stores without payment for the items. Tags have also been disposed on articles in railroad cars to indicate the movement of the items in the railroad cars along the tracks. In the systems now in use, the tags have a single design and a single construction. This has limited the utility of the systems.
In recent years, different systems have been provided for communicating on a wireless basis between a pair of spaced positions. Each of the systems employs a different technology of wireless communication. Different systems have also been provided in recent years for locating the positions of mobile items. Each of these systems employs a different location technology. It would be desirable to provide a universal system which would be responsive to all of the different types of wireless communications between a pair of spaced positions and would be responsive to all of the different technologies for locating the positions of mobile items. It would also be desirable to make these systems so flexible in their concept and operation that they could also incorporate new wireless communication technologies and new location technologies in the future without affecting the operation of the existing wireless communication technologies and the existing location technologies in the system.